Shield Electrode Layout for Touch Display Crosstalk Reduction
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Solution Overview
Problem
The presence of parasitic capacitance between touch sensing and display driving electrodes in touch display devices leads to performance drops and accuracy issues in touch sensing, as well as abnormalities in display driving.
Innovation Solution
A touch display device structure is implemented with a shield electrode disposed between the touch sensing and display driving electrodes, and strategically positioned to minimize overlap with data lines, reducing direct and indirect coupling and enhancing touch sensing performance without increasing the number of layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If touch electrodes and display electrodes are disposed in overlapping areas to maximize touch sensing coverage, then touch sensing area is improved, but parasitic capacitance increases causing performance degradation
Solution Approach 1:
The touch electrode is divided into multiple segments (first touch electrode, second touch electrode, third touch electrode) with different overlap configurations relative to data lines. Some segments overlap with data lines while others avoid overlap, allowing the system to maximize overall sensing area while controlling parasitic capacitance in specific regions.
Solution Approach 2:
Different regions of the touch electrode are designed with different overlap characteristics. The first touch electrode overlaps with the first data line, the second touch electrode overlaps with the second data line, while the third touch electrode avoids overlapping with the third data line. This local differentiation optimizes the balance between sensing area and parasitic capacitance.
2Measurement precision
If shield electrodes are added to reduce parasitic capacitance effects, then touch sensing accuracy is improved, but device complexity increases
Solution Approach 1:
The shield electrode is designed to serve multiple functions simultaneously: it acts as a shielding element to reduce parasitic capacitance effects on touch sensing, while also functioning as a display electrode for display driving. This multi-functionality allows the system to improve touch sensing accuracy without adding extra layers, thereby avoiding increased device complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration improves touch sensing performance by reducing parasitic capacitance effects, preventing display driving abnormalities, and maintaining touch sensing accuracy while minimizing the number of layers required.
Implementation Method 1
a parasitic capacitance can be made between the electrode for the display driving and the touch electrode for a touch sensing
Data Source
AI summary
A touch display device includes a shield electrode disposed between a touch electrode and a display electrode, by not disposing the touch electrode and the shield electrode on a part of an area overlapping with a data line, thus direct and indirect coupling by the data line can be reduced and a crosstalk by a coupling between a touch signal and a display signal can be reduced. Furthermore, in the case that the shield electrode is disposed on a layer where a connecting pattern connecting between the touch electrode and the touch line is disposed, by maintaining an arrangement of the shield electrode on some area where the data line is overlapped and the touch electrode isn't disposed, thus an effect of a coupling reduction can be provided while maintaining a noise blocking performance of the shield electrode stably.